topic RE: Object invoked error in Product Forum

Object invoked error

Vijay_KumarMata — Wed, 10 Jul 2019 05:29:00 GMT

Hi,

I'm getting an error saying "object invoked has been disconnected" while running a process. I'm not sure why BluePrism through the error. After attach\activate error still persists. Can you help out to resolve the issue.

Regards,
Vijay Kumar

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Vijay Kumar Matampalli
System Engineer
Fidelity Information Services
Indian/Christmas
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RE: Object invoked error

HazemFarajallah — Wed, 10 Jul 2019 08:25:00 GMT

hello,

it can happen if you call an object from another "which is not recommended", can you give us more details.

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Hazem Farajallah
RPA-developer
e-on
Europe/Stockholm
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RE: Object invoked error

Vijay_KumarMata — Wed, 10 Jul 2019 08:43:00 GMT

Hi,

Thanks for your answer!!!

Please find the screenshot for reference.

Regards,
Vijay Kumar.

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Vijay Kumar Matampalli
System Engineer
Fidelity Information Services
Indian/Christmas
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RE: Object invoked error

HazemFarajallah — Wed, 10 Jul 2019 09:30:00 GMT

are you using excel vbo?

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Hazem Farajallah
RPA-developer
e-on
Europe/Stockholm
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RE: Object invoked error

Vijay_KumarMata — Wed, 10 Jul 2019 09:40:00 GMT

Hi Hazem,

Yes!! we do use excel VBO

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Vijay Kumar Matampalli
System Engineer
Fidelity Information Services
Indian/Christmas
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RE: Object invoked error

david.l.morris — Wed, 10 Jul 2019 10:09:00 GMT

Why would it be not recommended to call one object from another?

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Dave Morris
3Ci @ Southern Company
Atlanta, GA
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RE: Object invoked error

HazemFarajallah — Wed, 10 Jul 2019 10:14:00 GMT

I can't really see how you are using it so i recommand you go through BP Excle VBO docs

https://portal.blueprism.com/system/files/2017-11/Excel%20Automation%20Guide.pdf

https://portal.blueprism.com/system/files/2017-11/Extending%20MS%20Excel%20VBO.PDF

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Hazem Farajallah
RPA-developer
e-on
Europe/Stockholm
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RE: Object invoked error

HazemFarajallah — Wed, 10 Jul 2019 10:17:00 GMT

Many things, if you take a look at the best practice 😉

for example memory usage? why calling two objects same time while you can call them from the process,

"that's my first process and I had very low memory issue "

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Hazem Farajallah
RPA-developer
e-on
Europe/Stockholm
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RE: Object invoked error

david.l.morris — Wed, 10 Jul 2019 10:24:00 GMT

I have read the best practice document and related documents many times and there's no mention of any performance concerns from calling one object from another. In fact, I would disagree and suggest that it is best practice to use levels of objects when building a reusable framework of objects. It would be severely limiting to suggest that objects should only be called from the process level and that objects cannot take advantage of other objects. That's like saying all functions should be directly called from the main method.

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Dave Morris
3Ci @ Southern Company
Atlanta, GA
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RE: Object invoked error

HazemFarajallah — Wed, 10 Jul 2019 10:44:00 GMT

here https://portal.blueprism.com/system/files/documents/Object%20Design%20Guide.pdf

Section 2.2 has described how this large object will be consumed into the memory of any resource pc that is
running any process that automates the ERP system in the example 😄

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Hazem Farajallah
RPA-developer
e-on
Europe/Stockholm
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RE: Object invoked error

david.l.morris — Wed, 10 Jul 2019 10:55:00 GMT

That's referring to the size of an object and that it's best practice to split actions up into separate objects so that processes do not need to load the whole thing into memory if they don't need to use it. This is not discouraging calling objects from other objects. You'll also notice that in several of the Blue Prism-provided VBOs, objects call other objects.

I agree that if you can call an object from the same layer (the process layer preferably), it could be best to do so. But, at the same time, I personally have never run into an issue of object instances causing memory issues. I've run into several other situations such as huge collections causing memory issues for sure. But I've even done recursive calls which can instantiate A LOT of instances of the object with no noticeable impact to memory. I'm not saying it's best to do that but I think you're underestimating the capability to load many instances of an object into memory.

Anyway, good discussion. I see your point as far as avoiding large objects being loaded into memory multiple times because they're called from various layers.

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Dave Morris
3Ci @ Southern Company
Atlanta, GA
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RE: Object invoked error

joakimeklund — Thu, 11 Jul 2019 06:49:00 GMT

I completely disagree, I see that it's absolutely worth having every call of objects from the process level. Mainly because it makes it easier for anyone who views the process since the flow is easier to follow (there's no need to dig deep), one get's to see exactly what actions are being used and the framework for how you build reuseable objects also enhanced, because you won't cram in a lot of interaction with an application in one action/object.

It is also stated in the "Blue Prism - Development Best Practice" document that this is how it should be as well (page 11) "Do not call published actions from within an object".

Kind Regards,

Joakim

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Joakim Eklund
Senior RPA Developer
Swedbank AB
Europe/Stockholm
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RE: Object invoked error

HazemFarajallah — Thu, 11 Jul 2019 06:55:00 GMT

🙂

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Hazem Farajallah
RPA-developer
e-on
Europe/Stockholm
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RE: Object invoked error

david.l.morris — Thu, 11 Jul 2019 10:36:00 GMT

@joakimeklund

Objects can have many purposes, including at least two big categories of utilities and application UI interaction. I'm assuming you're more referring to objects that handle interaction with a specific application. Is that right? Because if so, I'm more referring to utilities such as strings or json. The reason you should not abandon allowing objects to call other objects is that you lose the ability for reuse in so many ways. Think of string manipulation. If I build an object that is supposed to retrieve data using a web service or even from the UI of an application, it is often necessary to do some string manipulation so that just the right value is passed back to the process or the object can do some validation to ensure the value was actually retrieved or whatever. We lose the opportunity for reuse if we don't call the Utility - Strings actions from within this object. Surely you wouldn't suggest that raw data be passed back to the process every time for you to build in logic to parse that data every time.

As I pointed out before, Blue Prism has already demonstrated the benefit of this. Look at the Webservices - REST object. It calls the Utility - JSON object, the Webservices - OAuth2.0 object, and the Utility - HTTP object. To require all object calls from the process level would mean much more complex logic than is necessary.

A further reason for allowing objects to call other objects is for unit testing. I often see Blue Prism processes designed with an excessive number of stages and pages. Because you cannot call into a Blue Prism process except to the Main Page, it becomes very difficult to unit test any logic within it. By moving the logic into objects that can be called at any point, you can enable both reuse and unit testing since you can call those object actions and testing specifically the logic inside them.

Another quick example to show what I mean. The most common interaction I see with the MS Excel VBO is Create Instance, Open Workbook, Get Worksheet As Collection, and Close Instance. It's not always like that but I see it very frequently. We built a reuse action in an object that takes the name of a workbook, etc. and performs those 4 actions for us. Now anytime I have the basic requirement of just getting the full collection of data from a spreadsheet, I only need to call one action to make that happen. This action can be called from inside of an object or from a process and it works really well.

For your second paragraph about page 11, this is different from what I was disagreeing with. It is talking about calling the actions in the same object because it's possible to use a page reference to refer to the same instance of the object rather than instantiate a new object instance. If you were disagreeing with my talking about recursion, I would agree with you that it's really not a great idea in Blue Prism due to memory limitations. I was merely noting that I've tested having a ton of instances of an object before with no noticeable issues but I wasn't suggesting it's a good idea.

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Dave Morris
3Ci @ Southern Company
Atlanta, GA
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